Insert for boiler and heater flues



7 April 20, 1937. E. SCHMITT 2,077,776

INSERT FOR BOILER AND HEATER FLUES Filed Dec. 15, 1935 INVENTOR ATTORNEYS Patented Apr. 20, 1937 UNITED STATES AT NT OFFICE 4 Claims.

This invention relates to new and useful improvements in heating apparatus, and relates particularly to inserts for boiler and heater flues. It relates more especially to inserts for the tubes of tubular boilers and the flues of round flue furnaces.

An object of the invention is to provide means for greatly increasing the heating effect of a given size of furnace, the invention comprising means whereby the hot gases of the furnace are caused to travel a path of increased length as compared with the length of the heater flues of the furnace and remain for a longer time in contact with the flue surfaces.

Another object is to provide means whereby as the hot gases of a furnace travel through its flues the said gases are agitated or mixed, particularly by the setting up of eddy or cross currents so that all the gases passing through the g flues are at some time during their passage brought into contact with the surface of the flues so that the maximum of heat is extracted from the gases before they are permitted to escape from the furnace.

Other objects and advantages will become apparent from a consideration of the following detailed description taken in connection with the accompanying drawing wherein there is shown a satisfactory embodiment of the invention. However, it is to be understood that the invention is not limited to the details disclosed but includes all such variations and modifications as fall within the spirit of the invention and the scope of the appended claims.

In the drawing:

- ,Fig. 1 is a vertical sectional view through the upper portion of a furnace boiler and the flues thereof and showing the inserts of the invention in place in the boiler flues;

Fig. 2 is a side elevational view on an enlarged scale. showing the forward portion of one of the inserts alone;

Fig. 3 is a top plan view of the device as shown in Fig. 2; and

Fig. 4 is an end elevational view of Fig. 2.

Referring in detail to the drawing at It] is generally indicated a steam boiler including flues H for the passage of the hot products of combustion. While a steam boiler is shown it is to be understood that this is only for or by way of example since the present invention is applicable to various types of round flue furnaces, including either steam, hot water, or hot air heaters.

Within the flues II are inserts generally designated l2 and shown alone and on an enlarged scale in Figs. 2, 3, and 4 of the drawing.

Such inserts will be made up in various sizes for different boilers or furnaces, but each includes a central elongated core l3 and spaced semi-disc like baffie members l4 and I5 rigid with and ex- 5 tending transversely of and inclined at an angle to the core at opposite sides thereof. It is particularly noted that the baflle members M are arranged in intersecting relation to the baffle memhers I 5. The baffle members each extend for only 10 one half turn about the core. It=is also to be noted the bafiies are substantially flat, and while the baflies M are substantially parallel and inclined in the same direction with respect to the core l3 and the longitudinal axis of this core, 15 they are inclined in the opposite direction from the inclination of the baffles I5.

' About the core the bafiie members are arranged in spaced pairs A, B, C, and D etc. along the length of the core and, of course, the number of 20 pairs of bafiles in any given insert will depend on the length of the insert. Each pair of bafile members comprises one member l4 and the member l5 opposite and in intersecting relation with it. Preferably the inserts have neat flts in the 25 flues so that it is only necessary to slide them into place. It will be noted from Fig. 3 that the baffles I4 and I5 of each pair cross each other at about the axis or core of the insert so that the free end portion of each bafiie is between the two free end portions of the opposite baffles of two adjacent pairs. Thus for example one free end portion [4a of bafile M of pair B is between the free end portions l5a. of the baffles l5 of pairs A and B while its opposite free end 35 portion Hlb is between the free end portions l5b of baffles 15 of pairs B and C. This arrangement alternately divides the streams of gases and causes them to unite with other divided streams.

. When an insert is within a flue it serves to direct the flow of hot gases therethrough in intersecting paths so that the gases are mixed or agitated while passing through a flue. Therefore gases not initially in engagement with the walls 5 of the flue are brought into engagement with such walls during passage through the flue.

Assuming hot gases to be entering the forward end of a flue or moving from left to right as viewed in Fig. 3, such gases will be immediately 50 divided as some pass rearwardly along the front surface of the baffle member l4 while others pass rearwardly along the front surface of the bafile member N3 of the pair of members A. Such gases moving rearwardly along said member M are 55 directed spirally downwardly between the members I of the pairs A and B and passing under the core move upwardly between said members and are divided by the member 14 of the pair B, a part of the gases passing rearwardly along each side of said member I4.

The gases passing rearwardly along the forward face of member l5 of pair A are directed upwardly between the members l4 of the pairs A and B and moving over the upper edge of member 15 of pair A and across the upper side of the core engage and mix with the gases moving rearwardly at the forward side of member I4 of the pair B.

These gases move spirally downwardly between the members l5 of the pairs B and C. However, the gases moving rearwardly between members IA of the pairs B and C are divided by the member l5 of pair C as such gases move downwardly. During downward movement the gases at the forward side of member I5 of pair C intersect and mix with the gases moving downwardly from the forward side of member 14 of pair B. This action is repeated for the length of the insert. Thus gases going down opening I! between baflles l4 and I5 of pair A will unite with the gases going down through opening l8. This resulting stream will come up through the openings I9 and 20 and so will be again divided by end Ma of baflle H of pair B. The gases that come up through opening l9 will unite with the stream between the two baffles M of pairs A and B while the gases that come up through 20 will unite with the stream between the two bailies l4 of pairs B and C or coming up through opening 2!, and so on throughout the length of the baffle and flue.

From the foregoing description taken with the drawing it will now be clear that the present insert divides the gases, passing through a flue, into two main spiral paths but that the paths intersect and are divided at each half turn of the spiral. Therefore at regular intervals the gases in the two paths are divided and collide with one another, and tending to move across one another are mixed. This mixing or agitating of the gases brings some of those previously at or toward the center of the insert out into engagement with the inner walls of the flue.

Such being the case at each half turn of the spiral paths, it will be appreciated that during passage through a flue all gases are continuously mixed and thrown against the walls of the flue so that a greater amount of heat is extracted from the gases. Also, the spiral paths and. dividing of the streams increase the distance the gases must travel while passing through a flue of given length so that there is a greater time interval for the transfer of heat from the gases to the flue. Therefore due to the increase in the length of travel of gases in the flue and due to the fact that at some one or more places during their travel through the flue all the gases are brought into engagement with its walls a boiler or other heater equipped with the insert will deliver more heat for the fuel consumed.

After the insert has been in place for a time the flue becomes caked with dirt or carbon and such dirt or carbon may be loosened from the walls of the flue by turning or rotating the insert in the flue. To facilitate this either or both ends of the core I2 is shaped, as by being flattened at IE, to receive a wrench or other tool. After turning the insert to loosen the dirt the latter will be scraped out of the flue as the insert is drawn from the flue. This thoroughly cleans the flues and facilitates keeping them in the proper clean condition for maximum heating and efficiency.

Having thus set forth the nature of my invention, what I claim is:

1. An insert for a gas flue of a heater comprising semi-disc like connected members arranged in two sets of spaced members on opposite sides of an axis, said members being also arranged inclined to the axis and with those in one set inclined in the opposite direction to those of the other set and with the ends of each member in alignment with spaces between two members on the opposite side of the axis.

2 An insert for a gas flue of a heater comprising an elongated central core, and spaced semidisc like bailie members arranged in two sets on opposite sides of said core, the members on one side being inclined in the opposite direction with respect to the axis of the core from those on the other side, said members being substantially flat and arranged with the ends of each member in alignment with spaces between adjacent members on the opposite side of the core.

3. In combination, a heater flue for combustion gases, an insert in the flue comprising spaced connected semi-disc shaped baflie members, said members being arranged in two sets on opposite sides of the axis of the flue and with the baffles in one set inclined to the axis in the opposite direction to those of the other set, and the ends of each baflle being spaced longitudinally of the axis from the ends of the bafiles on the opposite side.

4. In combination, a heater flue for combustion gases, an insert in said flue comprising a plurality of spaced, substantially flat, connected semi-disc like members, the members being arranged in two sets on opposite sides of the axis of the flue and the members in one set being inclined to the axis in a direction opposite to that of the other set, and the ends of each member being located in alignment with a space between two adjacent members of the other set to break up and separate the current of gases flowing between the members.

" EDMUND SCHMI'I'I. 

